Encapsulation of food ingredients

ABSTRACT

Oxygen sensitive oils or oils containing oil soluble oxygen sensitive substances are encapsulated in proteins which have been reacted with carbohydrates that contain reducing sugar groups. An aqueous mixture of a protein preferably casein and a carbohydrate preferably a sugar is heated within the range of 60 to 160° C. so that Maillard reaction products are formed in the aqueous mixture. The oil phase, up to 50% by weight is then emulsified with the aqueous phase to form micro encapsulated oil particles. The formation of MRP may also be done after emulsification prior to drying. The emulsions can be used as food ingredients or dried to form powders

[0001] This invention relates to the preparation of food ingredientsincluding oxygen sensitive oils or oil soluble ingredients.

BACKGROUND TO THE INVENTION

[0002] Oxygen sensitive oils or oxygen sensitive oil soluble ingredientsare a significant class of food ingredients. Because of theirsusceptibility to oxidation the ingredients need to be in a form that isprotective as well as enhancing their ease of use. Oils that are ofcommercial significance which fall into this category are generallythose containing polyunsaturated fatty acids.

[0003] These ingredients need to be prepared in a form suitable asingredients for general foods, novel foods, functional foods andnutraceuticals and to be storage stable under the usual transportconditions. Usually the ingredients are processed into stableoil-in-water emulsions or stable powders depending on their end use.

[0004] Powdered oils are generally formed by encapsulating the oil inprotein forming an emulsion and drying the emulsion to form a powderedoil. Japanese patent 5030906 discloses such a product made by mixingdiacetyl ester tartrate monoglyceride and edible oil in an aqueoussodium caseinate solution, emulsifying and drying to form a powder.

[0005] Japanese patent 5098286 discloses the encapsulation ofunsaturated fatty acids, such as gamma-linolenic acids, with hydrolysedproteins such as lactalbumin, lactoglobulin and casein to preventoxidation of the acids.

[0006] Hydrolysed proteins vary in activity according to the degree ofhydolysation and this may vary with different oils. Further thestability of the protein film encapsulating the oils is not alwayssatisfactory. The protection against oxidation is primarily due to thehydrolysed protein preventing contact between oxygen and the unsaturatedfatty acids rather than an antioxidant effect of the encapsulant.

[0007] U.S. Pat. No. 5,601,760 also discloses micro-encapsulation ofmilk fat and orange oils using whey proteins as the encapsulant. Thispatent also suggests that the whey proteins can be mixed withcarbohydrates. U.S. Pat. No. 5,143,737 discloses an animal feedsupplement composed of an unsaturated oil encapsulated in a wheysolution containing lactose which has been dried to form a powder andthen browned to form a Maillard reaction product in the encapsulatingmatrix.

[0008] It is an object of this invention to provide an encapsulant thathas good encapsulating properties and is also an antioxidant to protectoxygen sensitive oils or oil soluble products.

BRIEF DESCRIPTION OF THE INVENTION

[0009] To this end the present invention provides an encapsulant foroxygen sensitive oils or oxygen sensitive oil soluble substances whichis prepared by reacting an aqueous mixture of a protein with acarbohydrate containing reducing sugar groups.

[0010] The reaction that occurs is between free amine groups of aminoacids in the protein and reducing sugar groups in the carbohydrate. Thistype of reaction is generally termed a Maillard reaction, typicallyoccurring in the non-enzymatic browning of foods. This reaction occursduring heat processing of foods. In this invention the Maillard reactionis accelerated by heating within the range of 60 to 160° C. Thisinvention is partly predicated on the realisation that Maillard reactionproducts [MRP] can exhibit anti-oxidation activity in the presence ofpolyunsaturated fatty acids. This invention also relies on the discoverythat these Maillard reaction products formed with selected film formingproteinaceous materials produce superior encapsulants for oxygensensitive oils or oil soluble ingredients. Although whey protein andcarbohydrate were proposed as encapsulants in Pat. No. 5,601,760 therewas no realisation that heating these ingredients together would greatlyimprove the resistance to oxygen deterioration whilst maintaining goodencapsulation properties.

[0011] Thus in one embodiment the present invention provides anoil-in-water emulsion of an oxygen sensitive marine oil or othernon-marine oxygen sensitive oil or an oxygen sensitive oil-solublesubstance encapsulated in a protein which has been heated in thepresence of a carbohydrate to form sufficient Maillard reaction productto protect the encapsulated oil from oxidation.

[0012] The oil is preferably an edible oil and the emulsion or thepowder obtained by drying the emulsion, is used as a food ingredient, aswell as in feed supplements.

[0013] The encapsulants of this invention are not only effectiveanti-oxidants but form stable robust films around the oil droplets.

[0014] Any protein useful in encapsulating oils can be used as theprotein component of this invention. A carbohydrate with a reducingsugar functional group is reacted with the protein. The protein ispreferably soluble and needs to be stable in the heating range of theMaillard reaction and includes casein, soy and whey proteins, gelatine,egg albumin and hydrolysed proteins with increased free amino acidgroups including soy protein hydrolysate. Care needs to be taken inreacting the protein and carbohydrate to ensure that the conditions donot result in gelling or coagulation of the protein, as this will renderthe protein incapable of forming a good film. The preferred protein is amilk protein especially casein or whey protein isolate. Casein is themost preferred protein in many applications because of its low cost andits greater resistance to gelling during the heat treatment to form theMaillard reaction products. For infant food applications whey proteinsare the preferred protein source.

[0015] The preferred carbohydrate is a sugar with a reducing grouppreferably selected from the group consisting of monosaccharides (eg:glucose, fructose), disaccharides (eg: maltose, lactose),trisaccharides, oligosaccharides and glucose syrups. Any reducing sugarsource may be used including honey. The amount of Maillard reactionproduct in the protein-carbohydrate mixture is critical as an amountsufficient to provide antioxidant activity for the period of theproduct's shelf life is needed. Preferably the minimum reaction requiredbetween the protein and carbohydrate prior to encapsulation consumes atleast 10% of the sugar present. The extent of Maillard reaction productformed can be monitored [for a particular protein/carbohydratecombination] by the degree of colour change that occurs. An alternativemeasure is to assay the unreacted sugar.

[0016] In another aspect of this invention there is provided a method offorming an oil-in-water emulsion of an oxygen sensitive oil or an oxygensensitive oil-soluble substance which includes the steps of:

[0017] a) Preparing an aqueous mixture of a protein and a carbohydratewhich contains a reducing sugar group

[0018] b) Heating the mixture from 60° C. to 160° C. for a period toallow sufficient Maillard reaction products to form without coagulation

[0019] c) Dispersing said oil phase into the aqueous phase.

[0020] The emulsion may be formed using any conventional homogenisationprocedure or by microfluidisation.

[0021] Preferably the emulsions have a volume median particle diameterup to 2 microns and the oil phase is about 25% by weight of theemulsion. Higher to levels of oil phase, up to 50% by weight, may alsobe prepared.

[0022] To form a powder the emulsion is dried by any conventional dryingmethod to a moisture content no greater than 5%. Such powders willconsist of up to about 80% w/w oil.

[0023] The protein content in the aqueous mixture is from 5 to 15% byweight with from 1 to 15% by weight of the carbohydrate. After heating,additional carbohydrate or protein or both ingredients may be added totake the protein: carbohydrate weight ratio to between 1:4 and 4:1. Thepreferred final ratios are between 1:2 and 2:1, depending on the type ofprotein and carbohydrate used. The quantity of protein and carbohydratewill depend on the amount of oil to be emulsified, the oxygensensitivity of the oil phase and the anticipated storage period for theproduct.

[0024] The pH of the aqueous phase is between 4 and 10 preferably 6 to8. The pH range of the aqueous phase will depend on the isoelectric pHof the protein used, which in turn influence protein solubility atvarious pHs.

[0025] The heating period will depend on the temperature to which theaqueous mixture is heated. For heat sensitive proteins lowertemperatures and longer heating periods may be appropriate. Thisinvention is partly predicated on the discovery that carrying out theMaillard reaction either before or after emulsification prior to dryingprovides a more robust emulsion or powder and avoids degradation of theoxygen sensitive oils.

[0026] The oils or oil soluble products useful in the present inventionare those used in food and pharmaceuticals, which are susceptible todeterioration by oxidation.

[0027] The oils include those that contain polyunsaturated fatty acids.

[0028] The oil phase is added to form an emulsion with up to 50% oil byweight. The emulsification is carried out so that the volume medianparticle size is less than 5 microns preferably less than 2 micronsdepending on the final ingredient application.

[0029] Throughout this specification the term an oxygen sensitive oilmeans an oil, fat, or an oil soluble product that is oxygen sensitivewhich is dissolved or dispersed in an oil phase.

[0030] The oils or oil soluble products useful in the present inventionare those used in food and pharmaceuticals, which are susceptible todeterioration by oxidation.

[0031] The oils include those that contain polyunsaturated fatty acidssuch as canola oil, borage oil, evening primrose oil, safflower oil,sunflower oil, flaxseed oil, wheat germ oil and grapeseed oil and marineoils obtained from fish such as tuna, herring, mackerel, sardine, codliver, and shark. Dairy fats or other fats that are oxygen sensitive canalso be encapsulated in accordance with this invention. Oil solubleingredients that need protection from oxidation include vitamin A[retinol], vitamin D [calciferol], vitamin E, tocopherols, tocotrienols,vitamin K [quinone] and beta-carotene [pro-vitamin-A].

[0032] The oil-in-water emulsions and powders made in accordance withthis invention are suitable as ingredients in making infant formulae,yoghurts, beverages, UHT drinks, pasta products, bread and bakeryproducts, processed cheese etc. They may also be used as an alternativesource of oils and fats in ice cream, dairy desserts, creamers, soupbases and filled dairy products. The encapsulants can also be used fornutraceutical applications.

[0033] The powders can be additionally coated to improve theirperformance such as coating with medium chain triglycerides [MCT] fornutritional benefit or with starch to improve the flowability of thepowders. Care has to be taken in selecting the protein and carbohydrateto be used as some discolour sufficiently and present a caramelisedflavour which may not be suitable for encapsulating some flavouringredients.

DETAILED DESCRIPTION OF THE INVENTION

[0034] A number of formulations were prepared some according to theinvention and some for comparative purposes.

[0035] Emulsion Formulations

[0036] Tuna fish oil was used as an oil of choice in most examples sinceit contains a high amount of long chain polyunsaturated fatty acids. Itis inherently unstable and oxidizes readily when exposed to air. Otheroils used in the examples include evening primrose oil (EPO) andanhydrous milk fat (AMF).

[0037] A range of formulations were prepared using protein and/orcarbohydrate and oil mixtures at different ratios. The formulations weremade-up to contain 40-60% fat in the final powder

[0038] The protein used in these examples was sodium caseinate, wheyprotein isolate (WPI), soy protein isolate (SPI), skim milk powder(SMP), hydrolysed casein (HCP) and hydrolysed whey protein (HWP). Thesugars used, alone or in combination, were glucose, lactose, sucrose,oligosaccharide and dried glucose syrup. A polysaccharide, high-methoxypectin or carrageenan, was added to protein-sugar mixtures in someformulations.

[0039] Emulsion Preparation

[0040] Generally the proteins were first dispersed in water at 50-60° C.and allowed to hydrate in the water bath for at least 30 minutes. Aportion or the whole amount of the carbohydrate was added into a portionor the whole amount of the protein solution. The pH was adjusted to thedesired pH (6.5 to 7.5). For enhancing formation of Maillard reactionproducts, these protein-carbohydrate mixtures were heated at 90-100° C.or refluxed for 30-90 min and cooled to 50° C. Where the whole amountsof protein or carbohydrates were not used, the remaining amount ofprotein or carbohydrate was added after the heat treatment. The oilheated to 50-60° C. was added into the protein-carbohydrate solutionusing a Silverson laboratory high shear mixer. This pre-emulsion mixturewas then homogenised at 50-60° C. and 350 bar pressure (single stage) or350 and 100 bar pressure (in two stages) using a Rannie laboratoryhigh-pressure homogeniser. In some cases, a microfluidizer operated at800 bar was used. In some cases additional carbohydrates were addedafter the dispersion of the oil into the heated protein-carbohydratesolution. The formation of MRP may also be done after emulsificationprior to drying.

[0041] Spray Drying of Emulsions

[0042] The emulsions were dried using a Drytec laboratory spray dryerwith a twin fluid nozzle at 2.0 bar atomising pressure. The feed washeated to 60° C. prior to atomisation and the inlet and outlet airtemperatures were 180° C. and 80° C. respectively.

[0043] Powder Free-fat Analysis

[0044] The free-fat content of powders was taken as an indication of theefficiency of encapsulation. The estimation of free fat in powder wasbased on the method by Pisecky (Handbook of Milk Powder Manufacture,1997, p206) except that petroleum ether was used in place of carbontetrachloride. Fifty ml of petroleum ether (b.p. 40-60° C.) was added to10 g powder. The mixture was agitated in a stoppered flask for 15minutes. The mixture was filtered and the solvent evaporated at 60° C.using a rotary evaporator. The remaining fat residue was then dried inan oven at 105° C. for 1 h.

[0045] Oil Droplet Size of Emulsions

[0046] The. size of the oil droplets in homogenised emulsions wasmeasured using a Mastersizer-X laser diffraction particle size analyser.The emulsion was sampled and added directly to the measuring cell. Thevolume median diameter D(v,0.5) was taken and used as indicator of theemulsion size.

[0047] Quick Powder Stability Test

[0048] Ten-ml vials were half filled with tuna oil powder samples andstored at 4 and 35° C. for 3 weeks. Eight panelists were asked to ratethe degree of freshness and rancidity of the powder samples stored at35° C. by sniffing the samples immediately after opening the vials. Eachof the samples was evaluated in 4 replicates by different panelists(trained and untrained) and the rancidity scores averaged and compared.The scores were used as a screening technique for evaluation of thedegree of deterioration of stored samples.

[0049] Propanal Headspace Analysis to Determine Stability of theMicrocapsules

[0050] Propanal was used as an indication of the oxidative stability ofthe prepared emulsions and the powdered oil. The powder or the emulsionsample (1 g) was sealed in a glass vial (20 ml), then equilibrated at40° C. for 30 minutes. A 10 ml of the headspace was analysed using aPerkin Elmer Model HS40 headspace auto-sampler and Perkin Elmer ModelAuto-system XL capillary gas chromatograph fitted with a DBI fusedsilica capillary column (30 m, 0.32 i.d., 4 micron film) and FIDdetector. The analysis was repeated on samples spiked with a knownquantity of propanal to obtain quantitative values for the analysis. Insome cases an internal standard (IS) 3-methylbutanal was used.

EXAMPLE 1

[0051] 1.1 Powders

[0052] Powders containing 40-60% fat containing Na-caseinate and sugarwere made using (a) heated Na caseinate-reducing sugar mixtures and (b)unheated Na caseinate -sugar mixtures as encapsulants. Lower rancid odorscores were generally obtained in the system containing heated(refluxed-30 min) Na caseinate-sugar mixtures compared to those thatwere not refluxed (heated 60° C.-30 min). Selected examples (40% fat,20% protein, 40% sugars) of powders made with refluxed and heated (60°C.-30 minutes) protein-sugar mixtures showed that refluxing improved theresistance of the powders to the development of rancid odor (Table 1.1).Similarly, trends were obtained with powders with added pectin (60%fat:13.3% protein: 26.6% sugars: 0.12% pectin), with refluxedcaseinate-sugar systems being superior encapsulants than those heated at60° C.-30 minutes (Table 1.1). TABLE 1.1 Characteristics of 40-60% fatpowders prepared from heated casein-sugar solutions showing the effectof heating on powder free fat and stability % Casein-% Sugar HeatTreatment Rancid Concentration of Protein-sugar Free Fat Odour ScoreOrder of processing at heating solution (g/100 g powder) 3 wks-35° C.Powders with 40% tuna oil, 20% Na-caseinate, 2.5% lactose, 37.5% sucroseReflux (with  9.8-1.2 reflux-30 min 1.8 2.0 lactose)- sugars-oil-homogPowders with 40% tuna oil, 20% Na-caseinate, 20% lactose, 20% sucroseHeat-(no sugar) 10-0 60° C.-30 min 2.1 3.8 sugars-oil-homog Powders with40% tuna oil, 20% Na-caseinate, 40% sucrose Heat-(no sugar) 10-0 60°C.-30 min 2.8 3.8 sugars-oil-homog Powders with 60% tuna oil, 13.3%Na-caseinate, 13.3% lactose, 10.7% sucrose, 2.5% glucose, 0.12% pectinReflux (with  8.2-1.5 reflux-30 min 7.4 1.8 glucose)- oil-sugars-homogPowders with 60% tuna oil, 13.3% Na-caseinate, 13.3% lactose, 13.2%sucrose, 0.12% pectin Heat-(no sugar) 10-0 60° C.-30 min 3.3 3.5sugars-oil-homog

[0053] 1.2 Emulsions:

[0054] Emulsions containing 14-20% fat were made using (a) refluxedNa-caseinate-sugar mixtures and (b) heated (60° C. -30 min) Na caseinate-sugar mixtures as encapsulants, and with or without added pectin. Allthe emulsions prepared produced fine emulsions of <2 μm (Table 1.2)TABLE 1.2 Characteristics of emulsions prepared from heated casein-sugarsolutions % Casein- % Sugar Heat Treatment Concentration ofProtein-sugar Emulsion Size Emulsion Formulation at heating solution D(0.5) μm Na-caseinate-sugar emulsions 14.3% tuna oil, 7.1% Na-caseinate, 9.8-1.2 reflux-30 0.75 0.9% lactose, 13.4% sucrose (with lactose) 14.3%tuna oil, 7.1% Na-caseinate, 10-0 60° C.-30 min 0.72 7.1% lactose, 7.1%sucrose 14.3% tuna oil, 7.1% Na-caseinate, 10-0 60° C.-30 min 0.65 14.3%sucrose Na-caseinate-sugar emulsions with added pectin 21.4% tuna oil,4.7% Na-caseinate,  8.2-1.5 reflux-30 1.74 4.7% lactose, 3.8% sucrose,(with glucose) 0.9% glucose, 0.04% pectin 21.4% tuna oil, 4.7%Na-caseinate, 10-0 60° C.-30 min 0.59 4.7% lactose, 4.7% sucrose, 0.04%pectin

EXAMPLE 2 Effect of Emulsions Total Solids at Homogenisation on PowderCharacteristics

[0055] 2.1 Powders

[0056] The effect of total solids of the emulsion at the time ofhomogenisation on the powder free fat was dependent on the type ofprotein encapsulant used (Table 2.1). With whey protein isolate-sugarsystems, higher solids concentration at homogenisation resulted in lowerpowder free fat but higher rancid odor score. However, withcaseinate-sugar system (Table 2.1) higher solids concentration athomogenisation increased both powder free fat and rancid odor score.TABLE 2.1 Characteristics of 60% fat powders made with emulsions havingdifferent total solids concentration. % Protein-% Sugar Rancid EmulsionConcentration Heat Treatment Free Fat Odour Score Total solids atheating of Protein solution (g/100 g powder) 3 wks-35° C. Powders with60% tuna oil, 13.3% Na-caseinate, 13.3% glucose, 13.3% lactose 36% 10-060°-30 min 3.5 2.3 46% 10-0 60°-30 min 7.5 3.8 Powders with 60% tunaoil, 13.3% WPI, 13.3% lactose, 13.3% sucrose 36%  7-0 90° C.-30 min  6.9 2.5 46% 10-0 90° C.-30 min   4.7 3.3

[0057] 2.2 Emulsions:

[0058] Emulsions containing 21-27% fat were made using (a) heatedprotein-reducing sugar mixtures and (b) unheated protein-sugar mixturesas encapsulants. The emulsions were prepared at different total solidsconcentration. The effect of total solids of the emulsion at the time ofhomogenisation on the emulsion size was dependent on the type of proteinencapsulant and concentration used to (Table 2.2). With whey proteinisolate-sugar systems, the emulsion size was the same. However, withcaseinate-sugar system (Table 2.2) larger emulsion size were observed asthe total solids increased. All the emulsions prepared produced fineemulsions of <2 μm. TABLE 2.2 Characteristics of emulsions withdifferent total solids concentration (same amount of other components).% Protein-% Sugar Emulsion Concentration Heat Treatment Emulsion SizeTotal solids at heating of Protein solution D (0.5) μm 21% tuna oil, 5%Na-caseinate, 5% glucose, 5% lactose 36% 7-0 60° C.-30 min 0.53 27% tunaoil, 6.3% Na-caseinate, 6.3% glucose, 6.3% lactose 46% 10-0  60° C.-30min 0.92 21% tuna oil, 5% WPI, 5% lactose, 5% sucrose 36% 7-0 90° C.-30min 0.77 27% tuna oil, 6.3% WPI, 6.3% lactose, 6.3% sucrose 46% 10-0 90° C.-30 min 0.77

[0059] Effect of Protein:Carbohydrate Ratio

[0060] 2.3 Powders

[0061] Powders containing 40-60% tuna oil were prepared with differentprotein to sugar ratios. In powder formulations with the same oilcontent: the powder free fat was lower when the ratio ofprotein:carbohydrate was 1:2 compared to when the ratio was 1:1 (table2.3). TABLE 2.3 Characteristics of 40-60% fat powders having differentprotein to sugar ratio. % Protein-% Sugar Rancid Concentration HeatTreatment Free Fat Odour Score Protein:Sugar Ratio at heating of Proteinsolution (g/100 g powder) 3 wks-35° C. Powders with 40% tuna oil,Na-caseinate-lactose system (36% total solids) 1:2 10-0 60°-30 min 3.43.5 1:1 14-0 60°-30 min 9.8 8.3 Powders with 60% tuna oil,WPI-lactose-sucrose system (36% total solids) 1:2  7-0 90° C.-30 min  6.9 2.5 1:1 10-0 90° C.-30 min   26.4 2.25

[0062] 2.4 Emulsions.

[0063] Emulsions containing 40-60% tuna oil were prepared with differentprotein to sugar ratios. All emulsions prepared had particle size of<2um, emulsion size was smaller in formulations withprotein:carbohydrate ratio of 1:2 compared to the ratio of 1:1 (table2.4). TABLE 2.4 Characteristics of 14-21% fat emulsions with 36% totalsolids having different protein to sugar ratio. % Protein-% SugarEmulsion Concentration Heat Treatment Emulsion Size Total solids atheating of Protein solution D (0.5) μm 14.3% tuna oil,Na-caseinate-lactose system (36% total solids) 1:2 10-0 60°-30 min 0.671:1 14-0 60°-30 min 0.98 21.4% tuna oil, WPI-lactose-sucrose system (36%total solids) 1:2  7-0 90° C.-30 min   0.77 1:1 10-0 90° C.-30 min  0.84

Effect of Stage of Oil Addition

[0064] 2.5 Powders

[0065] The results showed that the addition of oil before the additionof carbohydrate resulted in lower powder free fat (Table 2.5). This maybe expected as the protein is not in competition with the carbohydrateat the time of emulsion formation. TABLE 2.5 Characteristics of 40-60%fat powders with different stage of oil addition during preparation. %Protein- % Sugar Rancid Stage of Concentration Heat Treatment Free FatOdour Score Oil Addition at heating of Protein solution (g/100 g powder)3 wks-35° C. Powders with 40% tuna oil, 20% Na-caseinate, 20% lactose,20% sucrose, 0.12% carrageenan (36% total solids)Ncas:carra:lac:suc:oil¹ 12-0 60°-30 min 3.7 6.3 Ncas:oil:carra:lac:suc²12-0 60°-30 min 2.4 4.5 Powders with 40% tuna oil, 20% Na-caseinate, 20%lactose, 20% sucrose, 0.12% pectin (36% total solids)Ncas:HMP:lac:suc:oil¹ 12-0 60°-30 min 1.9 3.0 Ncas:oil:HMP:lac:suc² 12-060°-30 min 1.0 3.3 Powders with 60% tuna oil, 13.3% Na-caseinate, 13.3%lactose, 13.3% sucrose (36% total solids) Ncas:oil:HMP:lac:suc²  8-060°-30 min 3.3 3.5 Powders with 60% tuna oil, 13.3% WPI, 13.3% lactose,13.3% sucrose (36% total solids) WPI:lac:suc:oil¹  7-0 90° C.-30 min  6.9 2.5 WPI:oil:lac:suc²  7-0 90° C.-30 min   5.3 3.3

[0066] 2.6 Emulsions

[0067] The results showed that the addition of oil before the additionof carbohydrate resulted in lower particle size (Table 2.6). This may beexpected as the protein is generally not in competition with thecarbohydrate at the time of emulsification and this result in theformation of a more uniform protein layer at the interface, whichresults in a better emulsion. TABLE 2.6 Characteristics of emulsionswith oil added at different stages during preparation. % Protein-% SugarEmulsion Concentration Heat Treatment Emulsion Size Total solids atheating of Protein solution D (0.5) μm 14.3% tuna oil,Na-caseinate-lactose-sucrose system with 0.12% carrageenan (36% totalsolids) Ncas:carra: 12-0 60°-30 min 0.75 lac:suc:oil¹ Ncas:oil: 12-060°-30 min 0.74 carra:lac: suc² 14.3% tuna oil,Na-caseinate-lactose-sucrose system with 0.12% pectin (36% total solids)Ncas:HMP: 12-0 60°-30 min 0.63 lac:suc:oil¹ Ncas:oil: 12-0 60°-30 min0.53 HMP:lac: suc² 21.4% tuna oil, Na-caseinate-lactose-sucrose systemwith 0.12% pectin (36% total solids) Ncas:oil:  8-0 60°-30 min 0.59HMP:lac: suc² 21.4% tuna oil, WPI-lactose-sucrose system (36% totalsolids) WPI:lac:  7-0 90° C.-30 min   0.77 suc:oil¹ WPI:oil:  7-0 90°C.-30 min   0.74 iac:suc²

EXAMPLE 3 To Illustrate the Effect of Different Processing Conditions on60% Tuna Oil Powder Characteristics with Casein-sugar Maillard ReactionProducts (MRPs) as Encapsulant

[0068] Powders containing 60% tuna oil, were prepared using MaillardReaction Products produced from the reaction of casein and sugars asencapsulants. A combination of different processing variables werechosen using fractional factorial design to investigate on the effectsof these variable on the powder properties and stability during storage.The oils were emulsified into the protein-sugar mixtures that had beenheated for at least 90° C. for 30 minutes or by refluxing the mixturefor 90 minutes. The emulsions were then homogenised and subsequentlydried into powders. The free fat content of the powders was determinedafter powder production and these ranged from 1-20% which was greatlyaffected by the combination of processing variables used. Samples ofpowder (80 g) were stored in 2 litre plastic containers to providesufficient oxygen in the headspace to accelerate oxidation of thesamples. These were stored at 35° C. for 4 weeks. Propanal, wasdetermined using gas chromatography (GC) (static headspace analysis).

[0069] The encapsulation efficiency and powder stability can thereforebe optimised by choosing the right combination of processing variablesand formulation (Table 3).

Effect of pH

[0070] The effect of pH (6.5 to 7.5) on propanal headspace concentrationwas significant (p<0.001). This result suggested that pH of the aqueouscasein-sugar solution at the time of heating was very important. Theresults clearly showed this trend where increasing pH from 6.5 to 7.5reduced the propanal concentration. This pH effect was consistent withthe different sugars used, with the change in casein-sugar ratio from1:1 to 1:2, and also when all or part of the sugar was heated (Table 3)

Effect of Sugar Concentration at Time of Heating to Form MRP

[0071] The effect of sugar concentration at time of heating on powderfree fat was significant (p=0.019). When sugar concentration at time ofheating is increased from 2.5% to 12% the resulting powders had lowerpropanal during storage. This effect is more significant when theprotein to sugar ratio is also much lower (Table 3)

Effect of Casein-sugar Ratio

[0072] The effect of casein-sugar ratio on propanal was significant(p=0.025). The results showed lower propanal concentration in storedpowders, when the amount of sugars are increased in the formulation.This suggests that powders with casein-sugar ratio of 1:2 were morestable against oxidation than powders with casein sugar ratio of 1:1(Table 3).

Effect of Homogenisation and Heat Treatment

[0073] There was some interaction between homogenisation and heattreatment. The interaction of homogenisation and heat treatment wassignificant (p=0.035). These results suggest that heat treatment athigher temperature and homogenisation of the emulsions in two-stages(350+100 bar) significantly improved powder stability (Table 3). TABLE 3Effect of pH, homogenisation, casein-sugar concentration at time ofheating, heat treatment temperature, casein:carbohydrate ratio, and typeof sugar, on the free fat and stability of high-fat powders using heatedcasein-sugar systems % Protein- Heat Propanal pH Homogenisation % SugarTreatment Free Fat (with IS) at time Pressure Concentration of Protein-(g/100 g 4 wks-35° C. of heating (bar) at heating sugar solution powder)(μg/g powder) Powders with 60% tuna oil, 13.3% protein, 13.3% glucose,13.3% dried glucose syrup 6.5 350 10-2.5 90° C.-30 min 3.89 50.9 7.0 35010-2.5 90° C.-30 min 5.03 20.3 7.5 350 10-2.5 Reflux-30 min 4.02 15.56.5 350/100  6-12  Reflux-30 min 5.10 17.0 7.5 350/100  6-12  90° C.-30min 1.66 9.3 Powders with 60% tuna oil, 20% protein, 10% glucose, 10%dried glucose syrup 6.5 350/100 10-2.5 90° C.-30 min 10.84 113.9 7.5350/100 10-2.5 Reflux-30 min 7.93 26.5 6.5 350 9-9  Reflux-30 min 5.0017.6 7.0 350/100 9-9  Reflux-30 min 9.54 6.8 7.5 350 9-9  90° C.-30 min5.77 10.5 Powders with 60% tuna oil, 13.3% protein, 13.3% lactose, 13.3%sucrose 6.5 350/100 10-2.5 Reflux-30 min 3.26 37.7 7.5 350/100 10-2.590° C.-30 min 4.00 24.5 6.5 350  6-12  90° C.-30 min 5.33 121.4 7.0350/100  6-12  90° C.-30 min 4.77 25.7 7.5 350  6-12  Reflux-30 min 6.127.9 Powders with 60% tuna oil, 20% protein, 10% lactose, 10% sucrose 6.5350 10-2.5 Reflux-30 min 12.98 209.7 7.0 350 10-2.5 Reflux-30 min 7.1664.7 7.5 350 10-2.5 90° C.-30 min 7.42 41.4 6.5 350/100 9-9  90° C.-30min 10.78 169.2 7.5 350/100 9-9  Reflux-30 min 6.45 7.3 Powders with 60%tuna oil, 13.3% protein, 3.3% glucose, 10% sucrose, 13.3% lactose 6.5350 10-2.5 Reflux-30 min 6.57 39.5 7.0 350/100 10-2.5 Reflux-30 min12.30 19.6 7.5 350 10-2.5 90° C.-30 min 4.57 22.6 6.5 350/100  6-12  90°C.-30 min 9.93 129.4 7.5 350/100  6-12  Reflux-30 min 2.87 5.7 Powderswith 60% tuna oil, 20% protein, 2.5% glucose, 7.5% sucrose, 10% lactose6.5 350/100 10-2.5 Reflux-30 min 13.62 58.8 7.5 350/100 10-2.5 90° C.-30min 12.45 62.4 6.5 350 9-9  90° C.-30 min 4.89 54.7 7.0 350 9-9  90°C.-30 min 5.20 44.8 7.5 350 9-9  Reflux-30 min 5.00 33.3 Powders with60% tuna oil, 13.3% protein, 26.6% dried glucose syrup 6.5 350/10010-2.5 90° C.-30 min 17.63 110.2 7.5 350/100 10-2.5 Reflux-30 min 7.0434.2 6.5 350  6-12  Reflux-30 min 10.53 28.6 7.0 350  6-12  Reflux-30min 10.45 18.81 7.5 350  6-12  90° C.-30 min 7.12 24.7 Powders with 60%tuna oil, 20% protein, 20% dried glucose syrup 6.5 350 10-2.5 90° C.-30min 13.24 149.0 7.0 350/100 10-2.5 90° C.-30 min 16.59 60.8 7.5 35010-2.5 Reflux-30 min 16.92 41.7 6.5 350/100 9-9  Reflux-30 min 13.8828.0 7.5 350/100 9-9  90° C.-30 min 20.71 124.1

EXAMPLE 4 To Demonstrate the use of MRP Formed from Whey Protein Isolate(WPI)-sugar Mixtures as Encapsulants

[0074] Powders containing tuna oil were prepared using Maillard ReactionProducts produced from the reaction of WPI and sugars as encapsulants.The oils were emulsified into the protein-sugar mixtures that had beenheated for at least 90° C. for 30 minutes or refluxed for 30 minutes.The emulsions were then homogenised or microfluidised and subsequentlydried into powders. The free fat content of the powders was determinedafter powder production and these ranged from 4-8%. Samples of powder(80 g) were stored in 2 litre plastic containers to provide sufficientoxygen in the headspace to accelerate oxidation of the samples. Thesewere stored at 35° C. for 4 weeks. Propanal, was determined using gaschromatography (GC) (static headspace analysis). MRP can be formed byreacting other proteins (other than casein) with sugars and used asencapsulants. Encapsulation efficiency and powder stability can beoptimised by choosing the right combination of processing variables andformulation (Table 4). TABLE 4 Characteristics of 45% fat powdersprepared from heated WPI solutions showing the effect of order ofprocessing, and type of sugars used on powder properties and stability %Protein-% Sugar Heat Treatment Propanal (with IS) Concentration ofProtein-sugar Free Fat 4 wks-35° C. Order of processing at heatingsolution (g/100 g powder) (pg/g powder) Powders with 45% tuna oil, 18.3%WPI, 18.3% glucose, 18.3% dried glucose syrup (homogenised) Heat(withsugar)- 8-16 90° C.-30 min 0.66 6.5 oil-homog Powders with 45% tuna oil,18.3% WPI, 18.3% lactose, 18.3% sucrose (homogenised) Heat(with sugar)-8-16 90° C.-30 min 0.46 11.1 oil-homog Powders with 45% tuna oil, 18.3%WPI, 18.3% glucose, 18.3% dried glucose syrup (microfluidised) Heat(nosugar)- 9-0  90° C.-30 min 0.49 12.0 sugars-oil-homog Heat(no sugar)-9-0  90° C.-30 min 0.30 8.3 oil-sugars-homog Heat(with sugar)- 8-16 90°C.-30 min 0.38 3.9 oil-homog Powders with 45% tuna oil, 18.3% WPI, 18.3%lactose, 18.3% sucrose (microfluidised) Heat(with sugar)- 8-16 90° C.-30min 0.36 12.0 oil-homog

EXAMPLE 5. To Demonstrate the use of MRP as Encapsulants for Blends ofTuna Oils with Higher Solid Fat Index

[0075] Powders containing tuna oil and blends were prepared usingMaillard Reaction Products produced from the reaction of WPI and sugarsas encapsulants. The oils were emulsified into the protein-sugarmixtures that had been heated at 60° C. 90° C. or refluxed for 30minutes. The emulsions were then homogenised and subsequently dried intopowders. The free fat content of the powders was determined after powderproduction and these ranged from 3-5%. Samples of powder (80 g) werestored in 2 litre plastic containers to provide sufficient oxygen in theheadspace to accelerate oxidation of the samples. These were stored at35° C. for 4 weeks. Propanal, was determined using gas chromatography(GC) (static headspace analysis).

[0076] Powders containing tuna oil blends were more stable to oxidationwhen MRPs were used as encapsulants (Table 5) TABLE 5 Characteristics of60% fat powders prepared from heated casein-sugar formulations usingtuna oil and a blend with higher solid fat index Heat Treatment %Casein-% Sugar Propanal (with IS) of Protein-sugar Concentration FreeFat 4 wks-35° C. Type of oil solution at heating (g/100 g powder) (μg/gpowder) Powders with 51% tuna oil, 9% hydrogenated palm oil, 13.3%protein, 13.3% glucose, 13.3% dried glucose syrup Tuna oil + HPO 60°C.-30 min 6-12 2.14 7.4 Tuna oil + HPO 90° C.-30 min 6-12 2.07 1.8 Tunaoil + HPO Reflux-30 min 6-12 1.43 1.3

EXAMPLE 6 Demonstration of the Minimum Extent of the Maillard ReactionProducts Required to Protect Tuna Oil in Powders and Emulsions AgainstOxidation

[0077] 6.1 Powders

[0078] Powders containing tuna oil were prepared using Maillard ReactionProducts produced from the reaction of casein and sugars asencapsulants. The oils were emulsified into the protein-sugar mixturesthat had been heated for at least 60° C. for 10 minutes up to 100° C.for 90 minutes. The emulsions were then homogenised and subsequentlydried into powders. The free fat content of the powders was determinedafter powder production and these ranged from 0.6 to 1.5%. Samples ofpowder (80 g) were stored in 2 litre plastic containers to providesufficient oxygen in the headspace to accelerate oxidation of thesamples. These were stored at 35° C. for 4 weeks. Propanal wasdetermined using gas chromatography (GC) (static headspace analysis).

[0079] The stability of tuna oil powders to oxidation, as indicated bythe level of propanal in the headspace of stored powders, was dependenton the degree of heat treatment (time/temperature) applied tocasein-sugar mixtures during the manufacture of these powders. Thestability of tuna oil powders to oxidation was improved by higher heattreatment of the protein-sugar mixture. The extent of protectionafforded to the finished powder increased with:

[0080] Increasing extent of the Maillard Reaction as measured by theamount of reacted sugar

[0081] Increasing the temperature of heat treatment applied tocasein-sugar mixtures from 60° C. to 100° C.

[0082] Increasing the time of heating applied to casein-sugar mixturesfrom 10 to 90 min at fixed temperature

[0083] At least ˜10% of the sugar in the protein-sugar mixtures has tobe reacted to obtain desirable levels of protection of the oils (Table6.1) TABLE 6.1 Levels of Reacted Sugar and Characteristics of tuna oilpowders prepared with differently heat-treated sugar-protein mixturesPropanal @ Heat Sugar 4 wks-35° C. Casein:sugar Treatment reacted Freefat (μg/g powder) ratio (° C.-min) (%) (% powder) with IS*Protein:carbohydrate ratio = 1:2 Casein-sugar mixtures used in Powderswith 50% tuna oil, 16.7% Na-caseinate, 33.3% glucose 1:2 60-30  0-1 ndNd 1:2 60-60  0-1 nd Nd 1:2 60-90  0-2 nd Nd 1:2 80-30  2-3 nd Nd 1:280-60  3-4 nd Nd 1:2 80-90  4-6 nd Nd 1:2 100-30    9-10 nd Nd 1:2100-60   12-14 nd Nd 1:2 100-90   17-20 nd Nd Protein:carbohydrate ratio= 1:2 Powders with 50% tuna oil, 16.67% Na-caseinate, 16.67% glucose,16.67% dried glucose syrup 1:2 60-30 nd 1.01 47.6 1:2 60-60 nd 0.58 45.81:2 60-90 nd 0.66 44.7 1:2 80-30 nd 0.72 27.7 1:2 80-60 nd 1.59 20.4 1:280-90 nd 0.76 12.3 1:2 100-30  nd 0.75 3.1 1:2 100-60  nd 0.88 1.7 1:2100-90  nd 1.54 0.9 Propanal @ Sugar 2 wks-room Casein:sugar Treatmentreacted Free fat (μg/g powder) ratio (° C.-min) (%) (% powder) with IS*Protein:carbohydrate ratio = 1:1 Powders with 50% tuna oil, 25%Na-caseinate, 25% glucose 1:1 no heat 0-3 Nd 8.9 1:1 60-10 3-6 Nd 6.51:1 60-30 6-7 Nd 2.7 1:1 98-30 12-13 Nd 0.7 Protein:carbohydrate ratio =2:1 Powders with 50% tuna oil, 33.3% Na-caseinate, 16.7% glucose 2:160-30 2-6 nd 4.3 2:1 98-30 12-14 nd 1.1

[0084] 6.2 Emulsions

[0085] Emulsions containing tuna oil were prepared using MaillardReaction Products produced from the reaction of casein and sugars asencapsulants. The oil was emulsified into the protein-sugar mixturesthat had been heated for at least 60° C. for 10 minutes up to 100° C.for 90 minutes, using a homogeniser. Emulsions were stored for 4 weeksat 4° C. and analysed. Propanal were determined using GC (staticheadspace analysis).

[0086] The stability of tuna oil emulsions to oxidation, as indicated bythe level of propanal in the headspace of stored emulsions, wasdependent on the degree of heat treatment (time/temperature) applied tocasein-sugar mixtures during the preparation of these emulsions. Thestability of tuna oil emulsions to oxidation was improved by heattreatment of the protein-sugar mixture. The extent of protectionafforded to the finished emulsions increased with:

[0087] Increasing extent of the Maillard Reaction as measured by theamount of reacted sugar

[0088] Increasing the temperature of heat treatment applied tocasein-sugar mixtures from 60° C. to 100° C.

[0089] Increasing the time of heating applied to casein-sugar mixturesfrom 10 to 90 min at fixed temperature

[0090] At least ˜10% of the sugar in the protein-sugar mixtures has tobe reacted to obtain desirable levels of protection of the oils (Table6.2) TABLE 6.2 Levels of Reacted Sugar and propanal from tuna oilemulsions prepared with different degrees of reacting the sugar-proteinmixtures Heat Sugar Propanal @ Casein:sugar Treatment reacted 20 wks-4°C. ratio (° C.-min) (%) (μg/g emulsion) with IS* Protein:carbohydrateratio = 1:2 Casein-sugar mixtures used in Emulsions with 18% tuna oil,6% Na-caseinate, 12% glucose 1:2 60-30  0-1 nd 1:2 60-60  0-1 nd 1:260-90  0-2 nd 1:2 80-30  2-3 nd 1:2 80-60  3-4 nd 1:2 80-90  4-6 nd 1:2100-30    9-10 nd 1:2 100-60   12-14 nd 1:2 100-90   17-20 ndProteinicarbohydrate ratio - 1:2 Emulsions with 18% tuna oil, 6%Na-caseinate, 6% glucose, 6% dried glucose syrup 1:2 60-30 nd na 1:260-60 nd 1.4 1:2 60-90 nd 1.4 1:2 80-30 nd 1.4 1:2 80-60 nd 1.1 1:280-90 nd 1.3 1:2 100-30  nd 0.3 1:2 100-60  nd 0.3 1:2 100-90  nd 0.4

EXAMPLE 7 Demonstration of the use of Maillard Reaction Products asEncapsulants for Tuna Oil and Other oils

[0091] 7.1 Powders

[0092] These examples demonstrate the use of MRP formed by reactingprotein-sugar mixtures as encapsulants for tuna oil and other oils. Theoils were emulsified into the protein-sugar mixtures that had beenheated for 60° C.-30 minutes or at 98° C.-30 minutes. Homogenisedemulsions containing tuna oil, evening primrose oil (EPO) or anhydrousmilk fat (AMF) was subsequently dried into powders. The free fat inpowder was determined after powder production and this ranged from 0.6to 2.2%. Samples of powder (80 g) were stored in 2 litre plasticcontainers to provide sufficient oxygen in the headspace to accelerateoxidation of the samples, and stored at 35° C. for 4 weeks. Propanal wasdetermined using GC (static headspace analysis).

[0093] Powders containing all oils tested (tuna oil, EPO or AMF) weremore stable to oxidation when MRPs were used as encapsulants (Table 7.1)TABLE 7.1 Characteristics of powders prepared containing 50% oil, 16.67%Na-caseinate, 16.67% glucose, 16.67% dried glucose syrup given differentheat treatments Propanal @ Propanal @ 13 wks- Heat 4 wks- 35° C. Type ofTreatment Free fat 35° C. (μg/g Oil (° C.-min) (% powder) (μg/g) **powder) ** Powders with 50% tuna oil, 16.67% Na-caseinate, 16.67%glucose, 16.67% dried glucose syrup Tuna oil 60-30 0.86 1.8 nd Tuna oil98-30 0.62 0.7 nd Propanal @ Hexanal @ 13 wks- Heat 13 wks- 35° C. Typeof Treatment Free fat 35° C. (μg/g Oil (° C.-min) (% powder) (μg/g) **powder) ** Powders with 50% evening primrose oil (EPO), 16.67%Na-caseinate, 16. 67% glucose, 16.67% dried glucose syrup EPO 60-30 2.1549.5 5.2 EPO 98-30 1.13 13.2 2.6 Powders with 50% anhydrous milk fat(AMF), 16.67% Na-caseinate, 16.67% glucose, 16.67% dried glucose syrupAMF 60-30 0.64 <0.1 0.4 AMF 98-30 0.62 <0.1 <0.1

[0094] 7.2 Emulsions

[0095] Emulsions containing tuna oil, evening primrose oil (EPO) andanhydrous milk fat (AMF) were prepared using Maillard Reaction Productsproduced from the reaction of casein and sugars as encapsulants. The oilwere emulsified into the protein-sugar mixtures after heating for 98° C.for 30 minutes, and homogenised. Emulsions were stored for 4 weeks at 4°C. and analysed. Propanal were determined using GC (static headspaceanalysis). TABLE 7.2 Characteristics of emulsions prepared containingdifferent types of oil Type of Heat Treatment Propanal @ 4 wks-4° C. Oil(° C.-min) (μg/g emulsion) ** Emulsions with 18% tuna oil, 6%Na-caseinate, 6% glucose, 6% dried glucose syrup Tuna oil 98-30 <0.1Type of Heat Treatment Hexanal @ 4 wks-4° C. Oil (° C.-min) (μg/gemulsion) ** Emulsions with 18% evening primrose oil (EPO), 6%Na-caseinate, 6% glucose, 6% dried glucose syrup EPO 98-30 0.3 Type ofHeat Treatment Propanal @ 4 wks-4° C. Oil (° C.-min) (μg/g emulsion) **Emulsions with 18% anhydrous milk fat (AMF), 6% Na-caseinate, 6%glucose, 6% dried glucose syrup AMF 98-30 <0.1

EXAMPLE 8 Extension of the use of Maillard Reaction Products asEncapsulants for the Protection of Lipid Soluble Vitamins

[0096] 8.1 Powders

[0097] The following example illustrates the use of Maillard ReactionProducts as encapsulants for lipid soluble vitamins. The protein hasbeen reacted with sugars at 60° C. for 30 minutes or at 98° C. for 30minutes to form the MRP, prior to forming the emulsions. Mixedcarotenoids in medium chain triglyceride (MCT) were emulsified into thecasein-sugar reacted solution and subsequently dried into powders. Thefree fat in powder was determined after powder production and thisranged from 2.0-2.5%. Carotene contents in powders were measured usingUV-visible spectroscopy. TABLE 8.1 Carotene contents in powders Mixedcarotenoids Type of Treatment Free fat after production Oil (° C.-min)(% powder) (mg/10 g powder) Powders with 15% mixed carotenoids and 35%medium chain triglyceride oil (MCT), 16.67% Na-caseinate, 16.67%glucose, 16.67% dried glucose syrup MCT + mixed 60-30 2.1 1500carotenoids MCT + mixed 98-30 2.5 1500 carotenoids

[0098] 8.2 Emulsions

[0099] The following example illustrates the use of Maillard ReactionProducts as encapsulants for lipid soluble vitamins in emulsion systems.Emulsions containing mixed carotenoids were prepared using MaillardReaction Products produced from the reaction of casein and sugars asencapsulants. Mixed carotenoids were emulsified into the protein-sugarmixtures after heating for 60° C. for 30 minutes or at 98° C. for 30minutes, and homogenised. Carotene contents in the emulsions weredetermined by UV-visible spectroscopy. TABLE 8.2 Carotene contents inprepared emulsions Mixed carotenoids Type of Treatment after productionOil (° C.-min) (mg/10 g emulsion) Emulsions with 5.4% mixed carotenoidsand 12.6% medium chain triglyceride oil (MCT), 6% Na-caseinate, 6%glucose, 6% dried glucose syrup MCT + mixed carotenoids 60-30 540 MCT +mixed carotenoids 98-30 540

EXAMPLE 9

[0100] Extension of the use of Maillard Reaction Products asencapsulants for the protection of long chain polyunsaturated (LCP) oilswith added Iron salt (Ferrous Sulfate)

[0101] 9.1 Powders

[0102] The following examples illustrate the use of Maillard Reactionproducts as encapsulants for the protection of long chainpolyunsaturated (LCP) oils with added Iron salt (Ferrous Sulfate). Theprotein has been reacted with sugars at 60° C. for 30 minutes or at 98°C. for 30 minutes to form the MRP, prior to forming the emulsions andsubsequently drying. Powders containing 50% tuna oil was dry blendedwith ferrous sulphate. Samples of powder (80 g) containing the Iron saltwere stored in 2 litre plastic containers to provide sufficient oxygenin the headspace to accelerate oxidation of the samples, and stored at35° C. for 4 weeks. Propanal was determined using GC (static headspaceanalysis).

[0103] With use of MRPs as encapsulants (formed at 98° C. for 30min),there was more protection of the oils in dry blends of tuna oil powdersand iron salt compared to corresponding samples with less severe heattreatment (Table 9.1) TABLE 9.1 Characteristics of tuna oil powders withIron Salt (Ferrous Sulfate) added after powder production. Iron Content#Propanal @ 4 wks- Type of Heat Treatment (mg/10 g powder 35° C. Oil (°C.-min) blend) (μg/g powder) ** Powders with 50% tuna oil blended withFerrous Sulfate, 16.67% Na-caseinate (Ncas), 16.67% glucose, 16.67%dried glucose syrup Tuna oil 60-30 14 1.8 Tuna oil 98-30 14 0.7 Powderswith 50% tuna oil, 16.67% whey protein isolate (WPl), 16.67% glucose,16.67% dried glucose syrup Tuna oil 60-30 14 1.3 Tuna oil 98-30 14 0.8

[0104] 9.2 Emulsions

[0105] Emulsions containing tuna oil were prepared using MaillardReaction Products produced from the reaction of casein and sugars asencapsulants. The oil were emulsified into the protein-sugar mixturesafter heating for 60° C. for 30 minutes or at 98° C. for 30 minutes, andhomogenised. Iron was added and dissolved into the emulsion afterhomogenisation. Emulsions were stored for 4 weeks at 4° C. and analysed.Propanal were determined using GC (static headspace analysis).

[0106] The higher level of secondary oxidation products, as indicated bythe anisidine value, in the sample that had been heated at 60° C. for 30min compared to that heated at 98° C. for 30 min demonstrated that MRPsafforded protection of the oils. As the peroxides are primary productsof oxidation, the low value in samples heated at 60° C. for 30 mincoupled with the higher anisidine value suggests that some of theperoxides had broken down to other products.

[0107] With use of MRPs as encapsulants (formed at 98° C. for 30min),there was more protection of the oil in Fe-fortified emulsions comparedto corresponding samples with less severe heat treatment (Table 9.2)TABLE 9.2 Characteristics of Tuna oil extracted from emulsionscontaining Iron Salt (Ferrous Sulfate) after 1 week storage at roomtemperature with light. Emulsions with 18% tuna oil, 6% na-caseinate, 6%glucose, 6% dried glucose syrup, and Ferrous Sulfate Iron PeroxideContent# DHA Value Type of Treatment (mg/10 g content (meq/ p-AnisidineOil (° C.-min) emulsion) % Area 1000 g) value Tuna oil 60-30 25 26.621.0 17.2 Tuna oil 98-30 25 26.78 11.2 12.5

EXAMPLE 10

[0108] Extension of the use of Maillard Reaction Products asEncapsulants for the Protection of Long Chain Polyunsaturated (LCP) Oilsin Combination with Selected Nutraceuticals

[0109] 10.1 Powders

[0110] The following examples illustrate the use of Maillard Reactionproducts as encapsulants for the protection of long chainpolyunsaturated (LCP) oils in combination with selected nutraceuticals.The protein has been reacted with sugars at 60° C. for 30 minutes or at98° C. for 30 minutes to form the MRP, prior to forming the emulsionsand subsequently drying. Powders containing 50% tuna oil was dry blendedwith selected nutraceuticals. Samples of tuna oil powder (80 g)containing either calcium, folate or isoflavone were stored in 2 litreplastic containers to provide sufficient oxygen in the headspace toaccelerate oxidation of the samples, and stored at 35° C. for 4 weeks.Propanal was determined using GC (static headspace analysis).

[0111] With use of MRPs as encapsulants (formed at 98° C. for 30min),there was generally more protection of the oils in dry blends of tunaoil powders and other nutraceuticals compared to corresponding sampleswith less severe heat treatment (Table 10.1) TABLE 10.1 Characteristicsof tuna oil powders with other nutraceuticals (Calcium, Folate,Isoflavone) added after powder production. Powders with 50% tuna oil,16.67% Na-caseinate (Ncas), 16.67% glucose, 16.67% dried glucose syrupand nutraceuticals Propanal @ Type of Treatment Calcium # 4 wks-35° C.Oil (° C.-min) (mg/10 g powder) (μg/g powder) ** Tuna oil 60-30 260 2.0Tuna oil 98-30 260 0.5 Propanal @ Type of Treatment Folate# 4 wks-35° C.Oil (° C.-min) (mg/10 g powder) (μg/g powder) ** Tuna oil 60-30 200 1.7Tuna oil 98-30 200 0.6 Propanal @ Type of Treatment Isoflavone# 4wks-35° C. Oil (° C.-min) (mg/10 g powder) (μg/g powder) ** Tuna oil60-30 30 2.3 Tuna oil 98-30 30 0.7 Powders with 50% tuna oil, 16.67%whey protein isolate (WPl), 16.67% glucose, 16.67% dried glucose syrupPropanal @ Type of Treatment Calcium # 4 wks-35° C. Oil (° C.-min)(mg/10 g powder) (μg/g powder) ** Tuna oil 60-30 260 1.2 Tuna oil 98-30260 0.6 Propanal @ Type of Treatment Folate# 4 wks-35° C. Oil (° C.-min)(mg/10 g powder) (μg/g powder) ** Tuna oil 60-30 200 1.0 Tuna oil 98-30200 0.7

EXAMPLE 11 Demonstration of the Effectiveness of Oligosaccharides inDeveloping Maillard Reaction Products for Encapsulation of Oils

[0112] 11.1 Powders The following examples illustrate the effectives ofoligosaccharides for the preparation of MRP's intended as encapsulantsfor tuna oil and other lipids.

[0113] Raftilose P95 (Mandurah Australia Pty Ltd) an oligosaccharidefrom chicory inulin was used in this example. The protein has beenreacted with sugars (glucose or oligosaccharide) at 60° C. for 30minutes or at 98° C. for 30 minutes to form the MRP, prior to formingthe emulsions and subsequently drying. The free fat in powders wasdetermined after powder production ranging from 0.6 to 3.6%. Samples ofpowder (80 g) was stored in 2 litre plastic containers to providesufficient oxygen in the headspace to accelerate oxidation of thesamples, and stored at 35° C. for 4 weeks. Propanal was determined usingGC (static headspace analysis) With use of MRPs as encapsulants (formedat 98° C. for 30min), there was more protection of the oil compared tocorresponding samples with less severe heat treatment (Table 11. 1)TABLE 11.1 Characteristics of powders with MRP's formed by using othertype of sugar Type of Treatment Free fat Propanal @ 4 wks-35° C. Oil (°C.-min) (% powder) (μg/g powder) ** Powders with 50% tuna oil, 16.67%na-caseinate, 16.67% glucose, 16.67% dried glucose syrup Tuna oil 60-300.86 1.8 Tuna oil 98-30 0.62 0.7 Powders with 50% tuna oil, 16.67%na-caseinate, 16.67% oligosaccharide, 16.67% dried glucose syrup Tunaoil 60-30 3.55 1.6 Tuna oil 98-30 2.54 0.7

[0114] 11.2 Emulsions

[0115] Emulsions containing tuna oil were prepared using MaillardReaction Products produced from the reaction of casein and sugars asencapsulants. The oil were emulsified into the protein-sugar mixturesafter heating for 98° C. for 30 minutes, and homogenised. Emulsions werestored for 4 weeks at 4° C. and analysed. Propanal were determined usingGC (static headspace analysis). TABLE 11.2 Characteristics of emulsionsprepared with MRP formed by using other type of sugar Type of TreatmentPropanal @ 4 wks-4° C. Oil (° C.-min) (μg/g emulsion) ** Emulsions with18% tuna oil, 6% Na-caseinate, 6% glucose, 6% dried glucose syrup Tunaoil 98-30 <0.1 Emulsions with 18% tuna oil, 6% Na-caseinate, 6%oligosaccharide, 6% dried glucose syrup Tuna oil 98-30 <0.1

EXAMPLE 12 Demonstration of the Effects of Different Stages of Formationof Maillard Reaction Products during Manufacture of Powders andEmulsions on Protection of Oils

[0116] 12.1 Powders

[0117] The following examples illustrate the effectives of MRP's formedeither before or after emulsification. The protein has been reacted withglucose and dried glucose syrup at 98° C. for 30 minutes to form theMRP, either before or after emulsification, and subsequently drying intopowders. The free fat in powder was determined after powder productionand this ranged from 0.7 to 2.3%. Powder samples (80 g) was stored in 2litre plastic containers to provide sufficient oxygen in the headspaceto accelerate oxidation of the samples, and stored at 35° C. for 4weeks. Propanal was determined using GC (static headspace analysis).

[0118] MRP formed at 98° C. for 30min either before or afteremulsification offers more protection to the oil compared tocorresponding samples with less severe heat treatment. (Table 12.1)TABLE 12.1 Characteristics of powders prepared with MRP reacted beforeor after emulsification. Powders with 50% tuna oil, 16.67% na-caseinate,16.67% glucose, 16.67% dried glucose syrup Propanal @ Order HeatTreatment Free fat 4 wks-35° C. of Processing* (° C.-min) (% powder)(μg/g powder)** heat-oil-homog¹ 60-30 0.65 1.7 heat-oil-homog¹ 98-301.34 0.8 Oil-homog-heat² 98-30 2.34 0.4

[0119] 12.2 Emulsions

[0120] Emulsions containing tuna oil were prepared using MaillardReaction Products produced from the reaction of casein and sugars asencapsulants. The stage of reaction (MRP formation) was either beforeemulsification (without oil) or after emulsification (in the presence ofoil). The MRP were formed by heating the mixtures at 98° C. for 30minutes, and homogenised. Emulsions were stored for 4 weeks at 4° C. andanalysed. Propanal were determined using GC (static headspace analysis).TABLE 12.2 Characteristic of emulsions prepared with MRP's reactedbefore or after emulsification. Emulsions with 18% tuna oil, 6%Na-caseinate, 6% glucose, 6% dried glucose syrup Order TreatmentPropanal @ 4 wks-4° C. of Processing (° C.-min) (μg/g emulsion)**heat-oil-homog¹ 98-30 <0.1 Oil-homog-heat² 98-30 <0.1

EXAMPLE 3 Effectiveness of Various Proteins for Preparation of MaillardReaction Products Intended as Encapsulants of Oils

[0121] 13.1 Powders

[0122] The following examples illustrate the effectives of otherproteins for the preparation of MRP's intended as encapsulants for tunaoil and other lipids. The different proteins used were sodium caseinate(Na-Cas), whey protein isolate (WPI), soy protein isolate (SPI) and skimmilk powder (SMP). These proteins have been reacted with sugars at 60°C. for 30 minutes or at 98° C. for 30 minutes to form the MRP, prior toforming the emulsions and subsequently drying. The free fat in powderswas determined after powder production ranging from 0.6 to 2.7%. Samplesof powder (80 g) was stored in 2 litre plastic containers to providesufficient oxygen in the headspace to accelerate oxidation of thesamples, and stored at 35° C. for 4 weeks. Propanal was determined usingGC (static headspace analysis)

[0123] With all the proteins used to form MRP as encapsulants (formed at98° C. for 30 min), there was more protection of the oil compared tocorresponding samples with less severe heat treatment. (Table 13.1)TABLE 13.1 Characteristics of powders prepared using different proteinsto form MRP's Type of Treatment Free Fat Propanal @ 4 wks-35° C. Protein(° C.-min) (% powder) (μg/g powder)** Powders with 50% tuna oil, 16.67%na-caseinate, 16.67% glucose, 16.67% dried glucose syrup Na-Cas 60-300.86 1.8 Na-Cas 98-30 0.62 0.7 Powders with 50% tuna oil, 16.67% WPI,16.67% glucose, 16.67% dried glucose syrup WPI 60-30 0.78 1.3 WPI 98-300.72 0.8 Powders with 50% tuna oil, 17.6% SPI, 16.7% glucose, 15.7%dried glucose syrup SPI 60-30 0.67 2.9 SPI 98-30 0.63 2.1 Powders with50% tuna oil, 42% SMP (17.6% protein, 24.3% lactose,), 8% glucose SMP60-30 1.98 2.5 SMP 98-30 2.72 0.3

[0124] 13.2 Emulsions

[0125] The following examples illustrate the effectives of otherproteins for the preparation of MRP's intended as encapsulants for tunaoil and other lipids. The different proteins used were sodium caseinate(Na-Cas), whey protein isolate (WPI), soy protein isolate (SPI) skimmilk powder (SMP), hydrolysed casein protein (HCP) and hydrolysed wheyprotein (HWP). These proteins were reacted with sugars at 98° C. for 30minutes to form the MRP, prior to forming the emulsions. Emulsions werestored at 4° C. for 4 weeks, and Propanal was determined using GC(static headspace analysis). TABLE 13.2 Characteristics of emulsionsprepared using different proteins to form MRP's Type of TreatmentPropanal @ 4 wks-4° C. Protein (° C.-min) (μg/g emulsion)** Emulsionswith 18% tuna oil, 6% Na-cas, 6% glucose, 6% dried glucose syrup Na-Cas98-30 <0.1 Emulsions with 18% tuna oil, 6% WPIs, 6% glucose, 6% driedglucose syrup WPI 98-30 <0.1 Emulsions with 18% tuna oil, 6.3% SPI, 6%glucose, 5.7% dried glucose syrup SPI 98-30 <0.1 Emulsions with 18% tunaoil, 15% SMP (6.3protein, 8.7% lactose), 3% glucose SMP 98-30 <0.1Emulsions with 18% tuna oil, 6% HCP, 6% glucose, 6% dried glucose syrupHCP 98-30 <0.1 Emulsions with 18% tuna oil, 7% HWP (0.4% lactose), 6%glucose, 5% dried glucose syrup HWP 98-30 <0.1

EXAMPLE 14 Application of a Secondary Coating Material to Powders

[0126] Application of secondary coating may enhance the shelf life ofthe powders by providing additional barrier to its surroundings or canbe used, as an alternative way to deliver desired ingredients. It canalso change the release properties of the encapsulated material byproviding controlled release or delayed release, allowing for specifictarget time or target place of release. Secondary coating materialswhich could be used to achieve the above desired outcomes may include afat/oil, fat mixtures, a fat and a non-fat mixture, polysaccharides,gels, hydrocolloids, shellac, acid crystals, proteins, gums etc. Theprocessing techniques employed to apply a secondary coating may includefluid bed processing (top spray or wurster application), pan coating,spray gelation and by spraying the material during blending (ribbonblender)

[0127] In this example powder containing 50% oil prepared using MRP fromthe reaction of protein and sugars was sieved through a 600 μm sieve anddivided into 500 g lots. Medium chain triglyceride (MCT) oil was used asthe secondary coating material, which was applied using a fluid beddryer-granulator (NIRO STREA-1). The spray nozzle was positioned abovethe bed for top spray coating.

[0128] The process conditions used in this example are as follows: Airvolume 80 m³ hr⁻¹ Product/Screen Pressure Drop 90 mmH₂O Nozzle AirPressure 80 kPa Product Temperature 25° C. Outlet Temperature 18° C.

[0129] The following table demonstrates the possibility of secondarycoating applications to enhance the encapsulated powder properties.Increase in powder free fat with each addition of the medium chaintriglyceride coat show that the fat coating spray applied was depositedon the powder surfaces. TABLE 14 Free fat analysis of powders withsecondary coating MCT coat addition Powder Free Fat (% w/w) (g/100 g) 08.9 1 9.8 2 11.0 4 12.1

CONCLUSION

[0130] The formulation and preparation of oil-in-water emulsions, is themost important step in the successful production of microencapsulatedfats and oil in emulsions or powders.

[0131] Very low powder free fat in tuna oil powders even at high oilloading has been achieved with the use of mixed protein-carbohydrateencapsulants. The mixed systems (protein-carbohydrate) investigatedusing Na-caseinate or whey protein isolate (WPI) in combination withsugars (glucose, sucrose, lactose, dried glucose syrup andoligosaccharide), and in some cases with polysaccharide (carrageenan orHigh-methoxy pectin) gave good powders. Powders formulated with heatedNaCas-sugar mixtures were generally more resistant to oxidation comparedto those made from unheated mixtures.

[0132] Other general conclusions are:

[0133] Dry free flowing powder with oil loading up to 80% may besuccessfully produced with the appropriate choice of encapsulants.

[0134] Increased level of sugars lowers the powder free fat, but alsoreduces powder recovery during drying. Thus the level of sugars has tobe carefully chosen to ensure adequate powder recovery during productionwhilst achieving low powder free fat.

[0135] Generally a lower total solids at the time of homogenisationlowers the powder free fat.

[0136] In mixed protein and carbohydrate systems a protein: carbohydrateratio of 1:2 is better than a ratio of 1:1, which was demonstrated bylower powder free fat and better protection of the oil from oxidation.

[0137] Heating all the caseinate and sugars of the aqueous phase byrefluxing or heating at 90° C. for 30 minutes afforded better protectionto powders against oxidation, than heating only part of the caseinateand part of the sugar used in the system.

[0138] In heated casein-sugar systems refluxing the mixture for 30minutes afforded better protection to powders against oxidation, thanheating at 90° C. for 30 minutes.

[0139] The pH of the of the casein-sugar mixture at the time of heatinghas significant effects on both the powder free fat and the resistanceof the powder to oxidation during storage; with heating at the higher pHof 7.5 being better than heating at pH 7 or at pH 6.5

[0140] The type of sugar used in combination with the protein has alsosome effect on the degree of protection from oxidation it can offerduring powder storage.

[0141] At least about 10% of the sugar in the sugar protein mixturesshould be reacted to obtain desirable levels of anti-oxidant protection

1. A powder containing an oxygen sensitive oil obtained by drying anemulsion of the oil, wherein the oil is encapsulated within a filmforming protein which, prior to drying to form the powder, has beenheated in solution, in the presence of a carbohydrate, for a time toprovide sufficient Maillard reaction products to provide resistance tooxidation.
 2. A method of forming an emulsion of an oxygen sensitive oilwhich includes the steps of: a) preparing an aqueous mixture of aprotein and a carbohydrate which contains a reducing sugar group b)heating the mixture from 60° C. to 160° C. for a period to allowsufficient Maillard reaction products to form without coagulation c)dispersing said oil in the aqueous phase. d) homogenising the mixture toobtain an emulsion
 3. A method as claimed in claim 2 in which at leastsome of the carbohydrate is added after the emulsion is formed and stepb) is carried out after step d).
 4. A method as claimed in claim 2 inwhich the total solids at homogenisation is less than 50% and theprotein:carbohydrate ratio is between 1:4 and 4:1.
 5. A method offorming a powder containing an oxygen sensitive product which includessteps a) to d) defined in any one of claims 2 to 4 followed by dryingthe emulsion to form a powder
 6. Powders obtained by the method of claim5
 7. Powders as claimed in claim 6, which are coated with a substance toalter the release properties of the powder.
 8. An emulsion obtained bythe method of claim
 2. 9. An emulsion of an oxygen sensitive substanceencapsulated in a film forming soluble protein which has been reactedwith sufficient carbohydrate to form Maillard reaction products in theencapsulation material.
 10. An emulsion of an oxygen sensitive substanceencapsulated in a mixture of a milk protein containing a major portionof casein and a carbohydrate having a reducing sugar group which hasbeen heated for a time to form sufficient Maillard reaction products toimpart antioxidant activity to the encapsulating mixture.